The Relation Between Penetration and Decay in Creosoted Southern Pine Poles

HE creosoted southern pine pole has been justly regarded as a long-lived unit of plant equipment. However, there have been enough instances of failure by internal decay during the first few years in line to focus attention on the poorer poles and to raise questions about the quality and probable length of service of creosoted poles in general. The data presented in this paper were obtained in the course of an investigation to determine how, when, and where decay starts in creosoted southern pine poles in line, and what proportion of the poles are decaying after different periods of service. The results of the study are of particular significance as a basis for engineering the treatment of poles in a satisfactory and economic manner. G E N E R A L CONCLUSIONS ABOUT DECAY IN POLES IN L I N E In the sections of the lines that were inspected the incidence of decay was definitely correlated with the depth of penetration of the creosote and the per cent of sapwood penetrated. When all of the 3102 inspected poles of all ages up to 26 years were taken together: (a) There were 62 failures, all of which had penetration less than 2.1 inches and 75 per cent of the sapwood thickness; and the 62 failures were 2.00 per cent of the total poles inspected; and (b) Of these failures 59, or 95.16 per cent, had penetration less than 1.8 inches and 60 per cent of the sapwood thickness. All the field evidence indicates that the inspected poles, when the sapwood had been well penetrated with creosote, were practically immune to destruction by wood-destroying fungi for a long time.